Light-excluding, multi-layered material

ABSTRACT

A multi-layered material for use in producing containers. The multi-layered material includes an inner layer, an outer layer, and a regrind layer disposed between the inner layer and the outer layer. The outer layer contains titanium dioxide and the regrind layer contains a dye selected from a group consisting of yellow dye and black dye.

BACKGROUND OF THE INVENTION

[0001] The present invention relates generally to a multi-layermaterial, and more particularly to a multi-layer material including aregrind layer containing a dye that is selected so as to protectlight-sensitive contents of the container from environmental light.

SUMMARY OF THE INVENTION

[0002] It is well-known that certain nutritional products are sensitiveto light. For example, low acid liquid food products typically containnutrients, including, but not limited to vitamins such as vitamin B2(riboflavin), that are sensitive to light. Exposure of such foodproducts to light can result in damage to the biological activity ofthese nutrients and/or to the taste or other characteristics of theproducts. This presents a particular challenge in the packaging of foodproducts, including medical and pediatric nutritional products, becausesuch products are subject to labeling requirements that require that thenutritional contents, e.g., vitamin contents, of the food product bespecifically identified. In those cases in which the listed nutritionalcontents are light-sensitive, there may be a reduction in the amount oractivity of one or more of the nutritional contents of the product overtime due to light exposure, thereby causing the food product to be outof compliance with its labeling. In such a situation, it may benecessary to reduce the shelf-life of the food product, and thusincrease the cost of the food product. Alternatively, it may benecessary to increase volume of the nutritional contents of the product,for example, by way of vitamin fortification, which also increases thecost of the food product. It is preferable that a light-protectivepackage be provided so that the nutritional contents of the productremain within the ranges specified in the labeling, thereby providing alonger shelf-life for the product.

[0003] U.S. Pat. No. 5,750,226 to Macauley, et al. discloses a bottledesigned to provide protection for light-sensitive products containedtherein. U.S. Pat. No. 5,750,226 is incorporated herein by reference, inits entirety. Macauley, et al. disclose a bottle having a multi-layeredwall structure. The wall includes inner and outer layers of food gradepolypropylene, a regrind layer positioned between the inner and outerlayers of food grade polypropylene, and a pair of high temperatureadhesive layers. The wall further includes barrier layer. The adhesivelayers serve to bond the other layers to the barrier layer. Titaniumdioxide is incorporated into the food grade polypropylene layers andinto the regrind layer in order to reduce light transmission through thewall. The titanium dioxide imparts a white color to each layer in whichit is present.

[0004] Titanium dioxide is an inert material that can be used in bothretort and aseptic packaging techniques. Titanium dioxide is areflective material, i.e., it works by reflecting light away from thecontents of the product. Although titanium dioxide effectively reflectslight having a wavelength above approximately 500 nanometers, it hasbeen found that some light having a wavelength below 500 nanometers isreflected when a bottle wall contains relatively high amounts oftitanium dioxide. However, as discussed in U.S. Pat. No. 5,750,226, highconcentrations of titanium dioxide can create significant problems inthe manufacturing of containers. In addition, it can be difficult toachieve high titanium dioxide concentrations in relatively thincontainer walls.

[0005] Although the bottle disclosed by Macauley, et al. providessignificantly enhanced light barrier characteristics over prior artbottles, it is desirable to provide new container that is constructed toprovide enhanced light barrier characteristics, even when the containerwall is relatively thin. In particular, it is desirable to provide acontainer that is constructed to reduce or eliminate the transmission oflight having the wavelengths that will tend to degrade the nutritionalcontents of a food product contained by the container.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] For a more complete understanding of the present invention,reference may be had to the following Detailed Description read inconnection with the accompanying drawings in which:

[0007]FIG. 1 is a cross-sectional view of a container wall materialconstructed in accordance with the present invention; and

[0008]FIG. 2 is a plan view of a bottle constructed of a multi-layermaterial in accordance with the present invention.

DETAILED DESCRIPTION

[0009] Container 10 of the present invention can have a variety offorms. As depicted in FIG. 2, container 10 is configured as a bottle 11for a liquid product. However, it will be appreciated that container 10can have a variety of forms without departing from the spirit and scopeof the present invention. For example, container 10 can be configured asa box, a barrel, a vial, or a tube without departing from the intendedscope of the invention. Further, container 10 can be the primarycontainer for the contents thereof, i.e., the contents are in directcontact with container 10, or container 10 can in the form of asecondary container, i.e., a light-protective barrier provided over aprimary container that is in direct contact with the contents.

[0010] Container 10 as described herein, and as depicted in FIG. 2, isparticularly suitable for use in the packaging and storage of medicaland pediatric nutritional products such as the products manufactured andsold by Abbott Laboratories through its Ross Products Division. Thelight barrier characteristics of container 10, as described in detailherein, provide enhanced protection for the nutritional contents, e.g.,vitamin contents, of such products. However, it is to be understood thatcontainer 10 of the present invention can be used in the packaging andstorage of other light-sensitive products without departing from theintended scope of the present invention.

[0011] Container 10 is constructed from a multi-layered wall material 12having an outer layer 14, an inner layer 16, and a regrind layer 18disposed between the outer layer 14 and the inner layer 16. Outer layer14 and inner layer 16 can be constructed of a variety of knownmaterials. In an embodiment of the present invention in which container10 is constructed to contain a food product, one of ordinary skill inthe art will appreciate that outer layer 14 and inner layer 16 can beconstructed of polypropylene, high density polyethylene (HDPE), and/orpolystyrene. It is not required that outer layer 14 and inner layer 16be constructed of the same material.

[0012] The thicknesses of outer layer 14 and inner layer 16 can varydepending on the packaging needs encountered. However, the U.S. Code ofFederal Regulations calls for inner layer 16 to have a thickness of atleast approximately 0.002 inches when container 10 is used to contain afood product. In an exemplary embodiment of the present invention, innerlayer 16 has a thickness of approximately 0.0036 inches, while outerlayer 14 has a thickness of approximately 0.0064 inches. In thisexemplary embodiment, outer layer 14 and inner layer 16 are constructedof HPDE, although, as above-discussed, other materials can be used. Alsoin this exemplary embodiment, regrind layer 18 has a thickness ofapproximately 0.0184 inches. One of ordinary skill in the art willappreciate that other wall thicknesses are possible without departingfrom the scope of the present invention.

[0013] Regrind layer 18 can be constructed from a variety of materials.For example, regrind layer 18 can be constructed from re-groundmaterial, virgin material, and/or a combination of re-ground and virginmaterials. Regrind layer 18 may further include colorants where thecolorants are contributed by the re-ground material and/or virgincolorants. The characteristics of regrind layer 18 will be described ingreater detail herein.

[0014] Multi-layered wall material 12 may optionally include an oxygenbarrier layer 24, as depicted in FIG. 1. Oxygen barrier layer 24 can beconstructed of a variety of known materials known to provide oxygenbarrier characteristics, e.g., ethylene vinyl alcohol (EVOH) and nylons.In one embodiment of the present invention, oxygen barrier layer 24 isconstructed of EVOH and has a thickness of approximately 0.0009 inches.However, it will be appreciated that oxygen barrier layer 24 can have avariety of thicknesses without departing from the scope of the presentinvention. For example, oxygen barrier layer 24 can of a thickness of0.0002 inches-0.002 inches.

[0015] In one embodiment of the present invention, outer layer 14 isbonded to oxygen barrier layer 24 by way of first adhesive layer 20.Regrind layer 18 is bonded to the opposite side of oxygen barrier layer24 by way of second adhesive layer 22. First and second adhesive layers20, 22 can be constructed of a variety of known adhesive materials knownto be useful in bonding materials of the type included in multi-layeredwall material 12. For example, first and second adhesive layers 20, 22can be constructed from polyolefin, e.g., a polyolefin layer having athickness of approximately 0.0004 inches.

[0016] In an alternative embodiment of the present invention, oxygenbarrier layer 24 is disposed between inner layer 16 and regrind layer18. In this embodiment, a first adhesive layer is used to bond oxygenbarrier layer 24 to inner layer 16, and a second adhesive layer is usedto bond oxygen barrier layer 24 to regrind layer 18. One of ordinaryskill in the art will recognize that oxygen barrier layer 24 can haveother positions relative to inner layer 16, regrind layer 18, and outerlayer 14.

[0017] In the embodiment of the present invention depicted in theaccompanying figures, oxygen barrier layer 24 is positioned betweenregrind layer 18 and outer layer 14. Placement of the oxygen barrierlayer 24 in this position protects layer 24 from moisture which mayrender it ineffective. In addition, placement of the oxygen barrierlayer 24 in this position moves the adhesive layers farther away fromthe contents of container 10. It will be appreciated that placing theadhesive layers farther away from the contents of container 10 isdesirable in those cases in which interaction between the adhesive andthe contents may be detrimental to the contents of container 10.

[0018] Outer layer 14 and/or inner layer 16 in the exemplary embodimentof the present invention may contain a light barrier additive such astitanium dioxide. The presence of titanium dioxide in outer layer 14will impart a white color to outer layer 14 which is aestheticallypleasing, thereby making multi-layered material 12 useful in themanufacture of containers for consumer products. Similarly, the presenceof titanium dioxide in inner layer 16 will impart a white color to innerlayer 16. When multi-layered material 12 is used in the packaging offood products, it may be desirable to provide a white-colored inner wallin order to provide an aesthetically pleasing appearance to the interiorof the package. Thus, when a customer looks into the interior of thepackage, he/she will see a white inner wall surrounding the productcontained in the package.

[0019] In the exemplary embodiment of the present invention, outer layer14 and inner layer 16 contain approximately 5% by weight titaniumdioxide. As above-discussed, the presence of 5% by weight titaniumdioxide in the outer layer 14 will give container 10 an overall whiteexterior color while the presence of titanium dioxide in the inner layer16 will give container 10 an overall white interior color. However, itis to be appreciated that the amount of titanium dioxide added to outerlayer 14 and/or inner layer 16 can be varied depending upon the desiredaesthetics for a container constructed from multi-layered material 12 aswell as the desired light barrier characteristics of multi-layeredmaterial 12. Further, it will be appreciated that the desired lightbarrier characteristics of multi-layered material 12 will be dependentupon the intended contents of container 10 as well as the intendedambient light conditions to which container 10, and the product therein,are to be exposed.

[0020] Regrind layer 18 also may contain titanium dioxide. It will beappreciated that the presence of titanium dioxide in regrind layer 18does not impact the aesthetics of a container constructed frommulti-layered material 12 because regrind layer 18 is not visible.Rather, titanium dioxide is added to regrind layer 18 solely for thepurpose of increasing the light barrier characteristics of multi-layeredmaterial 12. Thus, it will be appreciated that the amount of titaniumdioxide added to regrind layer 18 can be varied depending upon thedesired light barrier characteristics of multi-layered material 12 anddepending upon the amount of titanium dioxide contained in outer layer14 and inner layer 16. That is, if outer layer 14 and inner layer 16contain little or no titanium dioxide, it will be appreciated that theamount of titanium dioxide incorporated into regrind layer 18 will haveto be increased in order to impart the desired light barriercharacteristics to multi-layered material 12 of the present invention.

[0021] In one embodiment of the present invention, regrind layer 18 isproduced using approximately 40% regrind material, for example, regroundmulti-layered material 12. In this embodiment, regrind layer 18 furtherincludes approximately 60% virgin material, e.g., virgin food gradepolypropylene material that does not contain titanium dioxide and acolorant, as discussed in detail herein. Thus, in this embodiment,regrind layer 18 contains approximately 2% by weight titanium dioxide.However, it will be appreciated that regrind layer 18 can be producedfrom different mixes of virgin and reground material, and that theamount of titanium dioxide and other colorant contained in regrind layer18 can be varied depending upon the desired light barriercharacteristics of multi-layered material 12.

[0022] Regrind layer 18 of the present invention contains a colorant ordye selected to reduce the transmittance through regrind layer 18 oflight having a wavelength less than 500 nanometers. In one embodiment ofthe present invention, a yellow colorant containing 1% by weight yellowdye and 99% by weight of a carrier resin, e.g., a high densitypolyethylene, is incorporated into regrind layer 18. The contents of thecarrier resin form no part of the present invention, as one of ordinaryskill in the art will appreciate that the type of carrier resin can bevaried depending upon the other materials used to constructmulti-layered material 12 of the present invention. It will beappreciated that the yellow dye will enhance the light barriercharacteristics of multi-layered material 12, thereby providing addedlight barrier characteristics to a package produced using multi-layeredmaterial 12. The yellow dye is effective at reducing the amount of lighttransmitted by multi-layered wall material 12, particularly light havingwavelengths less than 500 nm.

[0023] In an alternative embodiment, regrind layer 18 contains a blackcolorant, e.g., carbon black. As above-discussed, the amount of blackcolorant used can be varied depending upon the desired light barriercharacteristics and the relative thicknesses of the layers ofmulti-layered material 12. The black dye is effective at reducing theamount of light transmitted by multi-layered wall material 12,particularly light having wavelengths less than 500 nm. Where the blackcolorant used is carbon black, it is preferable that the carbon black beprovided in pelletized form, for reasons that are well known to those ofordinary skill in the art.

[0024] Black colorant and yellow colorant have been found to be equallyeffective in reducing the amount of light having wavelengths less than500 nm that is transmitted through multi-layered material 12 of thepresent invention, although it will be appreciated that the blackcolorant will be effective at reducing the transmission of light at allvisible wavelengths, while yellow colorant is effective at wavelengthsbelow 500 nm. In addition, it has been found that the use of blackcolorant in accordance with the present invention reduces thetransmission of ultraviolet light through multi-layered material 12.Thus, by using black colorant, it is possible to protect contents ofcontainer 10 from visible and ultraviolet wavelengths. For example, ithas been found that vitamin A is susceptible to degradation when exposedto ultraviolet light. It will be appreciated that additives other thanblack colorant can be included in multi-layered material 12 in order toreduce or block the transmission of ultraviolet light therethrough.

[0025] In one embodiment of a multi-layered wall material 12 produced inaccordance with the present invention, outer layer 14 constitutes 20.5%by weight of the multi-layered wall material 12. Outer layer 14 in thisexample includes 89.3% by weight of virgin high density polyethylene and10.7% by weight of a white colorant containing 80% by weight titaniumdioxide. One of ordinary skill will appreciate that outer layer 14contributes 2.2% by weight of white colorant to multi-layered wallmaterial 12, and that because 80% of the white colorant is titaniumdioxide, that outer layer 14 contributes 1.8% by weight of titaniumdioxide to multi-layered wall material 12.

[0026] In this embodiment of the present invention, multi-layered wallmaterial 12 further includes first and second adhesive layers 20, 22which collectively constitute 1.35% by weight of multi-layered wallmaterial 12. First and second adhesive layers are constructed from apolyolefin material in this embodiment of the present invention.

[0027] Also in this embodiment, inner layer 16 constitutes 12.5% byweight of the multi-layered wall material 12. Inner layer contains 89.3%by weight of virgin high density polyethylene and 10.7% by weight of awhite colorant containing 80% titanium dioxide and 20% by weight of anappropriate carrier resin. Thus, inner layer 16 contributes 1.07% byweight of titanium dioxide to multi-layered wall material 12.

[0028] Also in this embodiment, multi-layered wall material 12 furtherincludes an oxygen barrier layer that constitutes 2.0% by weight of themulti-layered wall material 12 and is constructed from 100% EVOH.

[0029] In this embodiment of the present invention, multi-layered wallmaterial 12 still further includes regrind layer 18 which constitutes62.3% by weight of the multi-layered wall material 12. Multi-layeredwall material 12 contains 59.5% by weight of virgin high densitypolyethylene and 39.6% by weight of reground, scrap material, where thescrap material is scrap of a multi-layered wall material 12 manufacturedin accordance with this first example. In addition, regrind layer 18contains 0.9% by weight of a yellow colorant. One of ordinary skill willappreciate that the addition of yellow colorant into regrind layer 18contributes 0.6% by weight of yellow colorant to the multi-layered wallmaterial 12. Assuming that the reground material incorporated intoregrind layer 18 contains 0.6% by weight of yellow colorant, thereground material contributes 0.14% by weight of yellow colorant tomulti-layered wall material 12. Thus, the yellow colorant in regrindlayer 18 constitutes 0.7% by weight of multi-layered wall material 12.In the first example, the yellow colorant contains 1% by weight ofyellow pigment or dye and 99% by weight of a carrier resin. Thus, theyellow pigment or dye in regrind layer 18 constitutes 0.007% by weightof the multi-layered wall material 12. It is to be appreciated that theyellow colorant can be replaced with a black colorant, asabove-discussed, without departing from the intended scope of thepresent invention.

[0030] In this embodiment of the present invention, multi-layered wallmaterial 12 contains both titanium dioxide and a yellow or black dye,each of which increases the light barrier characteristics ofmulti-layered wall material 12. In this example, multi-layered wallmaterial 12 contains 0.007% by weight of yellow pigment/dye and 3.5% byweight of titanium dioxide.

[0031] It will be appreciated that variations of this embodiment of themulti-layered wall material 12 of the present invention can be producedwithout departing from the intended spirit and scope of the presentinvention. For example, the amounts of titanium dioxide and yellow orblack dye included in multi-layered wall material 12 can be varieddepending upon the desired light barrier characteristics for a containerproduced using multi-layered wall material 12. In this regard, it willbe appreciated that the desired light barrier characteristics for apackage should be determined based upon the light sensitivity of theproduct to be contained in a package produced using multi-layered wallmaterial 12, as well as the amount and type of light to which theproduct will be exposed during manufacturing, storage, and sales displayof that product.

[0032] In the above-discussed example of a multi-layered wall material12 constructed in accordance with the present invention, it was assumedthat the resulting regrind layer 18 contains 0.7% by weight of yellowdye, where 0.6% by weight of yellow dye is contributed by the directloading of yellow dye and 0.14% by weight of yellow dye is contributedby yellow dye contained in the reground material. It will be appreciatedthat this example assumes that the amount of yellow dye contained inmulti-layered wall material 12 has reached a steady-state, i.e., thatthe system used to construct multi-layered wall material 12 has beenoperated for a time sufficient to achieve a state in which the amount ofyellow dye contained in multi-layered wall material 12 is no longerincreasing or decreasing. In this way, all multi-layered wall material12 produced contains a predetermined amount of yellow dye. Asabove-discussed, the yellow dye can be replaced with a black dye.

[0033] Although the multi-layered wall material 12 of the presentinvention has been described herein with respect to certain exemplaryand preferred embodiments, one of ordinary skill in the art willappreciate that various modifications to multi-layered wall material 12can be made without departing from the intended spirit and scope of thepresent invention, as defined by the appended claims.

What is claimed is:
 1. A multi-layered material comprising: an inner layer; an outer layer; a regrind layer disposed between said inner layer and said outer layer; said outer layer containing titanium dioxide; and said regrind layer containing a dye selected from a group consisting of yellow dye and black dye.
 2. A multi-layered material in accordance with claim 1, wherein said inner layer contains titanium dioxide.
 3. A multi-layered material in accordance with claim 1, further comprising an oxygen barrier layer, a first adhesive layer, and a second adhesive layer, said first adhesive layer constructed to bond said oxygen barrier layer to an outer surface of said regrind layer, and said second adhesive layer constructed to bond said oxygen barrier layer to an inner surface of said outer layer.
 4. A multi-layered material in accordance with claim 3, wherein said oxygen barrier layer is constructed from a material comprising ethylene vinyl alcohol.
 5. A multi-layered material in accordance with claim 1, wherein said dye is yellow dye.
 6. A multi-layered material in accordance with claim 1, wherein said dye is black dye.
 7. A multi-layered material in accordance with claim 1, wherein said regrind layer contains titanium dioxide.
 8. A package for a light-sensitive product, said package comprising: an inner layer; an outer layer having an inner surface; a regrind layer disposed between said inner layer and said outer layer, said regrind layer having an outer surface; a first adhesive layer disposed adjacent said outer surface of said regrind layer; a second adhesive layer disposed adjacent said inner surface of said outer layer; an oxygen barrier layer disposed between said first adhesive layer and said second adhesive layer, said first and second adhesive layers constructed to bond said oxygen barrier layer to said regrind layer and to said outer layer, respectively; said outer layer containing titanium dioxide; and said regrind layer containing a dye selected from a group consisting of yellow dye and black dye.
 9. A package in accordance with claim 8, wherein said inner layer contains titanium dioxide.
 10. A package in accordance with claim 8, further wherein said regrind layer contains titanium dioxide.
 11. A package in accordance with claim 8, wherein said oxygen barrier layer is constructed from a material comprising ethylene vinyl alcohol.
 12. A package in accordance with claim 8, wherein said dye is yellow dye.
 13. A package in accordance with claim 8, wherein said dye is black dye.
 14. A package in accordance with claim 8, wherein said regrind layer comprises a virgin high density polyethylene material and a reground material.
 15. A package for containing a light-sensitive product, said package comprising: titanium dioxide; and a dye selected from a group consisting of yellow dye and black dye.
 16. A package in accordance with claim 15, wherein said package is constructed from a multi-layered material.
 17. A package in accordance with claim 16, wherein said multi-layered material includes an outer layer, an inner layer, and a regrind layer, and wherein said dye is present in said regrind layer.
 18. A package in accordance with claim 17, wherein said titanium dioxide is present in said outer layer.
 19. A package in accordance with claim 17, wherein said titanium dioxide is present in said regrind layer.
 20. A package in accordance with claim 17, wherein said titanium dioxide is present in said inner layer. 